JP3540236B2 - Method and apparatus for automatically generating resistance check test program - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for automatically generating a resistance check test program, and more particularly to a method and an apparatus for automatically generating a resistance check test program for evaluating the resistance value of a resistance element in a semiconductor integrated circuit (IC) by a tester.
[0002]
[Prior art]
Conventionally, a resistance check that evaluates the resistance value of a resistance element inside an IC by a tester (hereinafter referred to as a tester evaluation) selects any two terminals from netlist information and searches for a resistance check route according to a combination of the two terminals. It was going by.
[0003]
Generally, as a method of adjusting the resistance value of a resistance element, a ground potential is applied to one terminal of the resistance element, and a current value flowing by applying a constant voltage to the other terminal is measured.
[0004]
Since the resistance value is obtained from the potential difference applied to both ends of the resistance element and the measured current value according to Ohm's law, the range of the current value corresponding to the desired resistance value range is set in the test standard by setting the range of the current value. Accurate tester evaluation becomes possible.
[0005]
Referring to FIG. 6, which shows a block diagram of a conventional resistance check test program automatic generation device for automatically creating a resistance check test program by a tester, this conventional resistance check test program automatic generation device has a specific algorithm. A resistance check test program generation tool 100 is provided, and receives a netlist information (hereinafter referred to as a netlist) 1, package information 2, test board information 3, tester information 4, and resistance accuracy information 5, and performs a resistance check test. Generate the program 200.
[0006]
Next, a conventional resistance check test program automatic generation method which is an operation of the conventional resistance check test program automatic generation device will be described with reference to FIG. , Package information 2, test board information 3, tester information 4, and resistance accuracy information 5 are input manually or automatically (step P1), and a net list 1 is searched and found in the net list 1. An arbitrary two terminals are selected from all the terminals (step P2).
[0007]
Next, a search is made for a resistor connected between the two terminals selected in step P1 (step P3).
[0008]
It is determined whether or not the searched route (hereinafter referred to as a searched route) has resistance for which checking has not been completed (step P4). If there is an uncompleted resistance, the process returns to Step P3.
[0009]
If there is no uncompleted resistance in Step P4, it is determined whether or not the search for all routes between the selected two terminals has been completed (Step 5). If the search for all routes has not been completed, the process returns to step P3.
[0010]
When the search of all the routes is completed in Step P5, the combined resistance value between the searched two terminals is calculated (Step P6).
[0011]
Next, a test standard is calculated based on the combined resistance value between the two terminals and the information 5 on the resistance accuracy, and resistance test information including the information of the selected two terminals, the combined resistance value and the test standard is generated and stored ( Step P7).
[0012]
Next, it is determined whether or not the route search has been completed for all combinations of terminals existing in the netlist 1 (step P8). If the search is not completed, the two terminals of the unfinished combination are selected (step P9), and the process returns to step P3.
[0013]
When the route search is completed for all the terminal combinations in Step P8, the stored resistance test information, package information 2, test board information 3, and tester information 4 are associated (Step P10).
[0014]
Finally, a resistance check test program 200 adapted to the tester format is generated (step P11).
[0015]
FIG. 8 is a circuit diagram showing an example of a resistance check route search of a circuit to be subjected to the conventional method for automatically generating a test program for checking resistance. Referring to FIG. 8, this circuit includes a power supply terminal TV for supplying power Vcc and a ground GND supply. , An input terminal TI, a reference voltage terminal TR, an output terminal TO, and resistors R1 to R10 each having a resistance value of 10, 30, 20, 5, 5, 2.5, 5 (KΩ). R7.
[0016]
Among them, the resistances R4 to R7 cannot be checked because the measurement route cannot be formed by the two terminals, and are excluded from the test target (indicated by x).
[0017]
Here, between the input terminal TI and the ground terminal TG, the resistor R3 can be checked. Between the power supply terminal TV and the reference voltage terminal TR, the resistor R1 can be checked, and the power supply terminal TV and the ground terminal TG can be checked. In between, the resistance values of the resistors R1 and R2 connected in series can be checked.
[0018]
However, the conventional test program automatic generation apparatus for resistance check and the method therefor search a resistance check route according to a combination of arbitrary two terminals among all terminals of a netlist, and search for a resistance check first searched. Since the route is preferentially reflected, there are the following problems.
[0019]
A first problem is that an unstable resistance check test program for measuring a small current caused by a high resistance value of a plurality of resistors connected in series may lower the yield.
[0020]
Referring to FIG. 9A, which is a circuit diagram showing a specific example of the first problem, this circuit includes a power supply terminal TV for supplying a power supply Vcc, a ground terminal TG for supplying a ground GND, and an input terminal TI, TS, a reference voltage terminal TR, three output terminals TO1, TO2, TO3, and resistors R1 to R7 each having a resistance value of 10, 25, 25, 55, 10, 5, 2, (KΩ). It is an analog processing circuit.
[0021]
In this circuit, for example, when the power supply terminal TV and the ground terminal TG are selected as the worst case resistance check route, the series connection resistance of the resistances R1 to R4 is measured.
[0022]
The second problem is that the test program becomes redundant because the same resistance is measured through a plurality of routes.
[0023]
Referring to FIG. 10A which shows a specific example of the second problem in a circuit diagram, this circuit includes a power supply terminal TV for supplying a power supply Vcc, a ground terminal TG for supplying a ground GND, and two input terminals. It has TI1 and TI2, an output terminal TO, and resistors R21 to R26.
[0024]
In this circuit, for example, when two routes of the input terminal TI2 and the ground terminal TG and the input terminal TI2 and the output terminal TO are selected as the worst case resistor check routes, the same resistors R22 and R23 are used for both routes. Will be included in duplicate.
[0025]
A third problem is that resistances having different types, accuracy, and values are measured simultaneously, and therefore, there is a possibility that a resistance value outside the specified range may be determined as a non-defective product.
[0026]
Referring to FIG. 11A which shows a specific example of the third problem in a circuit diagram, this circuit is the same as FIG. Here, the values of the resistors R1, R2, and R3 are 10, 30, and 20 (KΩ) as described above, and their allowable accuracies are 5, 10, and 20 (%), respectively.
[0027]
In this circuit, for example, when the input terminal TI and the power supply terminal TV are selected as the worst-case resistance check route, the series connection resistance of the resistors R3, R2, and R1 is measured, but the accuracy and the value are different. Since the resistance is measured simultaneously, for example, the resistor R1 has an error of 20% out of the standard, that is, an error of 2KΩ, and if there is no other error, it corresponds only to 3.3% of the total resistance value of 60KΩ. It is determined to be a good product.
[0028]
The above three problems arise for the following reasons.
[0029]
That is, a resistance check test program is automatically generated when a resistance between any two terminals is searched and an unsearched resistance is included. Therefore, when a resistance value is high due to a series connection of a plurality of resistances. However, a test program for measuring the high resistance as it is (first problem), a test program for measuring the same resistance through a plurality of routes (second problem), and simultaneously measuring resistances having different types, accuracy, and resistance values. It is likely to generate a test program (third problem).
[0030]
[Problems to be solved by the invention]
The above-described method and apparatus for automatically generating a resistance check test program search for a resistance check route according to a combination of any two terminals among all terminals in the netlist, and the resistance search route searched first has priority. When the resistance check route includes an unsearched resistance, a resistance check test program is automatically generated, and a plurality of resistances are caused by a high resistance value connected in series. An unstable resistance check test program for measuring a minute current has a drawback of lowering the yield.
[0031]
Further, since the same resistance is measured through a plurality of routes, there is a disadvantage that the test program becomes redundant.
[0032]
Furthermore, since resistances having different types, accuracy and values are measured simultaneously, there is a drawback that a non-defective product is determined even if the resistance value is out of the standard range.
[0033]
SUMMARY OF THE INVENTION It is an object of the present invention to improve the yield by reducing the measurement margin by generating a stable resistance check test program, to prevent multiple measurements of the same resistance, prevent the test program from being redundant, and use different types of resistors. It is an object of the present invention to provide a method and an apparatus for automatically generating a resistance check test program which reduce the simultaneous measurement of resistance and improve the guaranteed quality of resistance.
[0034]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a method for automatically generating a resistance check test program. In a method of automatically generating a resistance check test program for generating a resistance check test program for evaluation by a tester,
Using the information of the power supply terminal and the ground terminal in addition to the netlist, all terminals of the internal circuit searched by the first terminal group consisting of the power supply terminal and the ground terminal, and terminals other than the power supply terminal and the ground terminal Into a second terminal group consisting of certain signal terminals,
By setting a resistance search route composed of arbitrary one terminal selected from each of the first and second terminal groups, the resistance search route is divided by the first terminal group that is a common terminal,
The resistance value of the resistance element is searched by searching the resistance search route in the direction from the second terminal group to the first terminal group.
[0035]
According to a second aspect of the present invention, there is provided a method for automatically generating a resistance check test program, comprising the steps of: In a method of automatically generating a resistance check test program for generating a resistance check test program for evaluation by a tester,
A first step of inputting input information including the netlist of the IC, resistance accuracy information, power supply terminal information, and ground terminal information;
All terminals of the searched internal circuit are grouped into a first terminal group consisting of the power supply terminal and the ground terminal, and a second terminal group consisting of signal terminals that are terminals other than the power supply terminal and the ground terminal, The resistance search route is divided by the first terminal group, which is a common terminal, by setting a resistance search route including an arbitrary one terminal selected from each of the first and second terminal groups. A second method of searching for a resistance of a resistance to be measured and calculating a test standard using a common terminal route division algorithm which is a specific algorithm for searching for a search route from the second terminal group in the direction of the first terminal group. Steps and
A third step of associating each of the input information and generating the resistance check test program based on the associated input information and the calculated test standard.
[0036]
The first step includes inputting the netlist of the IC, package information, test board information, tester information, the resistance accuracy information, and the input information including power supply terminal information and ground terminal information. Is also good.
[0037]
The second step extracts all terminals of the netlist, classifies the power terminals and the ground terminals into the first terminal group based on the power terminal information and the ground terminal information, and Classifying signal terminals other than terminals into the second terminal group;
Selecting a two-terminal search root terminal composed of an arbitrary one terminal from all the terminals of the first terminal group and all the terminals of the second terminal group; and selecting a first terminal from the second terminal group. A twenty-first step of searching for a route of the resistor connected between the two search route terminals selected only in the direction to the group;
It is determined whether or not there is an unselected terminal of the first terminal group in a search route that is a route of the resistor searched in the twenty-first step, and if there is an unselected terminal, the process returns to the twenty-first step. 22 steps,
In the 22nd step, if there is no unselected terminal, it is determined whether or not there is an element other than a resistor in the search route. If there is an element other than a resistor, the process returns to the 21st step. When,
In the twenty-third step, if there is no element other than a resistor in the search route, it is determined whether or not the entire route between the selected two terminals has been searched. A twenty-fourth step returning to the step of
In the twenty-fourth step, when the search of the all routes is completed, a twenty-fifth step of obtaining a combined resistance value of all the resistances of the search route and calculating a test standard based on the information of the resistance accuracy,
A twenty-sixth step of storing the information of the two selected search route terminals, the combined resistance value, and the test standard;
A twenty-seventh step of determining whether or not the route search has been completed for all combinations of the terminals of the first terminal group and the second terminal group;
In the twenty-seventh step, when the route search is not completed for the combination of all the terminals, terminals of the combination for which search has not been completed are selected one terminal at a time from the first terminal group and the second terminal group. A twenty-eighth step returning to the twenty-first step S21;
In the twenty-seventh step, when the route search is completed with the combination of all the terminals, a combination of any two terminals of the second terminal group is selected as the search root terminal, and the selected search root terminal is selected. A second terminal group resistance searching step of searching for a combination of terminals of all the second terminal groups for the resistance connected between the two terminals.
[0038]
Further, a twenty-ninth step is that the resistance search step of the second terminal group selects a route composed of an arbitrary combination of two terminals of the second terminal group as the search route;
A thirtieth step of searching for a resistance connected between the two terminals of the selected search route;
Determining whether there is a terminal of the first terminal group in the search route, and if there is a terminal of the first terminal group, a 31st step of returning to the 30th step;
In the thirty-first step, if there is no terminal of the first terminal group, it is determined whether or not there is an element other than a resistor in the search route, and if there is an element other than a resistor in the search route, A thirty-second step returning to the thirtieth step;
In the thirty-second step, when there is no element other than the resistor in the search route, it is determined whether or not the search of all the routes of the selected two terminals is completed, and the search of all the routes of the selected two terminals is performed. Is not completed, a 33rd step returning to the 30th step;
A step of calculating a test standard based on the information of the resistance accuracy by obtaining a combined resistance value of the search route when the search of all the routes of the selected two terminals is completed in the 33rd step; ,
A thirty-fifth step of storing the information of the selected two terminals, the combined resistance value and the test standard;
A thirty-sixth step of determining whether or not a route search has been completed for all combinations of terminals in the second terminal group;
A step of selecting the two terminals of the unselected combination from the second terminal group and returning to the thirtieth step if the route search is not completed in the thirty-sixth step. good.
[0039]
A resistance check test program automatic generation device according to the present invention receives input information including a netlist of an internal circuit of a semiconductor integrated circuit (hereinafter, IC) to be measured, and uses an IC tester to determine the resistance value of a resistance element inside the IC. In a resistance check test program automatic generation device including a resistance check test program generation tool for generating a resistance check test program for evaluation,
The netlist of the IC, the power terminal information and the ground terminal information, the package information, the test board information, the tester information, and the resistance accuracy information are input,
A first terminal group including a power supply terminal and a ground terminal, wherein the resistance check test program generation tool utilizes information of a power supply terminal and a ground terminal in addition to the netlist, and searches all terminals of the IC internal circuit; The resistance search route is divided into a second terminal group consisting of signal terminals which are terminals other than the power supply terminal and the ground terminal, and a resistance search route consisting of arbitrary one terminal selected from each of the first and second terminal groups. By setting, the resistance search route is divided by the first terminal group which is a common terminal, and the resistance search route is searched from the second terminal group toward the first terminal group by searching for the resistance search route. It has a common terminal route division algorithm which is a specific algorithm for searching for the resistance value of the resistance element.
[0040]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings.
[0041]
The method and the apparatus for automatically generating a resistance check test program according to the present embodiment include, in addition to spice netlist information (hereinafter, a netlist) of an internal circuit of a semiconductor integrated circuit (hereinafter, an IC) to be measured, which has been used so far. Utilizing the information of the power supply terminal and the ground terminal, all the terminals of the IC internal circuit searched are made up of a first terminal group consisting of the power supply terminal and the ground terminal, and a second terminal group consisting of the signal terminals other than the power supply terminal and the ground terminal. A first terminal which is a common terminal by setting a resistance search route (path) consisting of an arbitrary one terminal selected from each of the first and second terminal groups. By dividing the resistance search route in groups and searching for the resistance search route in the direction from the second terminal group to the first terminal group. It is characterized in searching a resistance value of the resistance element.
[0042]
FIG. 4 is a block diagram showing an embodiment of the present invention in which components common to those in FIG. 6 are denoted by common reference characters / numerals, and FIG. 4 is a block diagram showing a resistance check test program according to this embodiment shown in FIG. The automatic generation device includes a resistance check test program generation tool 10 having a common terminal route division algorithm 11 which is a specific algorithm, and has a common netlist information (hereinafter referred to as a netlist) 1, a package information 2, and a test board. The power supply terminal information and the ground terminal information 6 are input in addition to the information 3, the tester information 4, and the resistance accuracy information 5, and a resistance check test program 20 is generated.
[0043]
The common terminal route division algorithm 11 utilizes the information of the power supply terminal and the ground terminal in addition to the netlist of the internal circuit of the IC to be measured, and searches all the terminals of the IC internal circuit for the first circuit including the power supply terminal and the ground terminal. And a second terminal group including signal terminals that are terminals other than the power supply terminal and the ground terminal, and each of the first and second terminal groups is composed of one arbitrary terminal selected from the first and second terminal groups. By setting the resistance search route, the resistance search route is divided by the first terminal group which is a common terminal, and the resistance search route is searched in the direction from the second terminal group to the first terminal group. This is to search for the resistance value of the resistance element.
[0044]
The definitions of the netlist information, test board information, tester information, resistance accuracy information, and power supply terminal information and ground terminal information will be described later.
[0045]
Next, with reference to FIG. 4 and FIG. 1 showing a processing operation in a flowchart, a schematic operation of a resistance check test program automatic generation method which is an operation of the resistance check test program automatic generation device of the present embodiment will be described. Input information including a netlist 1, package information 2, test board information 3, tester information 4, resistance accuracy information 5, power supply terminal information, and ground terminal information 6 of a semiconductor integrated circuit (IC) to be measured. Input (step S1).
[0046]
Next, a route search for the resistance to be measured and a test standard are calculated using the common terminal route division algorithm 11 (step S2).
[0047]
Next, the input information is associated with each other, and the resistance check test program 20 is generated based on the net list 1 constituting the input information, each input information and the calculated test standard (step S3).
[0048]
Next, the detailed operation of the method of automatically generating a resistance check test program according to the present embodiment will be described with reference to FIGS. 2 and 3 which show the details of steps S1 to S3 in a flowchart in FIG. The input information including the package information 2, the test board information 3, the tester information 4, the resistance accuracy information 5, the power supply terminal information, and the ground terminal information 6 is input manually or automatically (step S11).
[0049]
Next, all the terminals of the netlist 1 are extracted, and the power supply terminals and the ground terminals are classified into the group 1 based on the power supply terminal information and the ground terminal information 6, and the other signal terminal information is classified into the group 2 (step S12). .
[0050]
Further, two terminal search root terminals each including an arbitrary one terminal are selected from all terminals of group 1 and all terminals of group 2 (step S13).
[0051]
Next, a route of the resistor connected between the two search route terminals selected in step S13 is searched (step S21). At this time, the search direction of the search route is limited to the direction from group 2 to group 1.
[0052]
Next, it is determined whether or not there is an unselected terminal of group 1 in the searched route (step S22). If there is an unselected terminal, the process returns to step S21.
[0053]
If there is no unselected terminal in step S22, it is determined whether there is an element other than the resistor in the searched route (step S23). If there is an element other than the resistor, the process returns to step S21.
[0054]
If there is no element other than the resistor in step S23, it is determined whether or not all routes between the selected two terminals have been searched (step S24). If the search for all routes has not been completed, the process returns to step S21.
[0055]
If the search of all the routes is completed in step S24, a combined resistance value of all the resistances of the searched route is obtained, and a test standard is calculated based on the resistance accuracy information 5 (step S25). The information of the selected two terminals, the combined resistance value, and the test standard are stored (step S26).
[0056]
Next, it is determined whether or not the route search has been completed for all combinations of the terminals of the groups 1 and 2 (step S27). If the route search for all combinations of terminals has not been completed, terminals of combinations for which search has not been completed are selected one by one from Group 1 and Group 2 (Step S28), and the process returns to Step S21.
[0057]
If the route search has been completed for all the terminal combinations in step S27, any two terminals from group 2 are selected as the search route terminals (step S29).
[0058]
Next, a resistor connected between the selected two terminals is searched (step S200).
[0059]
Next, it is determined whether the searched route (search route) has a terminal of group 1 (step S201). If there is a group 1 terminal, the process returns to step S200.
[0060]
If there is no group 1 terminal in step S201, it is determined whether or not there is any element other than the resistor in the search route (step S202). If there is an element other than the resistor in the search route, the process returns to step S200.
[0061]
If there is no element other than the resistor in the search route in step S202, it is determined whether the search of all routes of the selected terminal is completed (step S203). If the search of all routes of the selected terminal is not completed, the process returns to step S200.
[0062]
If the search of all routes of the selected terminal is completed in step S203, a combined resistance value of the searched route is obtained, and a test standard is calculated based on the information 5 of the resistance accuracy (step S204).
[0063]
The information of the selected two terminals, the combined resistance value, and the test standard are stored (step S205).
[0064]
Next, it is determined whether or not the route search has been completed for all the combinations of the terminals of group 2 (step S206). If the route search has not been completed, two terminals of an unselected combination are selected from group 2 (step S207), and the process returns to step S200.
[0065]
When the route search is completed in step S206, the stored information, the package information 2, the test board information 3, and the tester information 4 are associated (step S208).
[0066]
Finally, the resistance check test program 20 is generated in conformity with the format of the tester (step S3).
[0067]
Next, the definition of terms used in the present embodiment will be described. First, the resistance check evaluates the resistance value of the resistance element inside the IC by a tester for DC characteristics test of the IC (hereinafter, DC tester). (Hereinafter referred to as tester evaluation).
[0068]
Therefore, the test program for resistance check means a test program for DC tester used when the resistance value of the resistance element inside the IC to be measured is evaluated by a tester.
[0069]
A general method for evaluating the resistance of a resistor by a tester is to measure the current flowing through the resistor by applying a ground potential to one terminal of the resistor and applying a constant voltage to the other terminal. is there.
[0070]
Since the resistance value is obtained from Ohm's law from the potential difference given to both ends of the resistance element and the measured current value, the resistance value is set by setting a current value range that matches the desired resistance value range in the test standard. Of the resistance value with respect to the standard value, that is, the tester evaluation of the resistance value accuracy becomes possible.
[0071]
However, in addition to the application of the voltage for resistance measurement and the current supply accompanying the measurement, it is necessary to set conditions such that no voltage is applied and no current is supplied to the power supply terminal and the ground terminal of the IC to be measured. That is, the potential difference applied to both ends of the resistive element (one terminal is set to the ground potential and corresponds to the voltage value applied to the other terminal) is the potential difference at which the transistor or diode built in the IC does not turn on (or operate). Although it depends on the device to be used, it is generally preferable that the voltage is 0.1 V to 0.3 V, which is a voltage at which the electrostatic protection diode connected to each terminal does not turn on (operate).
[0072]
Here, considering the empirical stability of the measurement, the measurement accuracy of a general DC tester, and the range of the resistance value generally used in the circuit, 0.2 V is set as the applied voltage at the time of the resistance check for convenience. .
[0073]
Next, it is very difficult to extract the power supply terminal information and the ground terminal information of the test target circuit and, in some cases, the reference voltage terminal information (such as the following) from the netlist. In particular, in a product using a plurality of power supplies, a complicated algorithm is considered to automatically extract power supply terminal information and ground terminal information from a netlist.
[0074]
Therefore, in order to efficiently and effectively create a resistance check test program, both a method of manually inputting power terminal information and ground terminal information and the like and a method of automatically extracting (determining by terminal name) are supported. It needs to be possible.
[0075]
In the case of manual input, since a plurality of power terminals and a plurality of ground terminals and a plurality of reference voltage terminals may exist depending on the circuit configuration, information is input for each group. The examples are shown below.
[0076]
In the first example, there are three groups of power supply terminals, ie, power supply terminals Vcc1, Vcc2, and Vcc3, and two groups of ground terminals, that is, ground terminals GND1 and GND2. , 15 pins, the power supply terminal Vcc2 has 10 pins, the power supply terminal Vcc3 has 8 pins and 32 pins, the ground terminal GND1 has 48 pins, and the ground terminal GND2 has 22 pins, 23 pins and 25 pins.
[0077]
The second example is an example in which the power supply terminal has one group of the power supply terminal Vcc1 and two groups of the reference voltage terminals VEE1 and VEE2. In each group, the power supply terminal Vcc1 has 11 pins, 12 pins, 18 pins, and the reference voltage The terminal VEE1 has 2 pins and 13 pins, and the reference voltage terminal VEE2 has 7 pins.
[0078]
Next, the test board information includes an IC terminal of an IC to be tested and a terminal of a test board (hereinafter referred to as an IC tester) for mounting the IC for testing the IC and electrically connecting the IC to a DC tester (hereinafter referred to as an IC tester). This means the connection information of the test board terminals. Normally, since a test circuit is formed on a test board, information may be stored as a netlist of the test circuit. In the present embodiment, the method of reading the netlist of the test circuit and manually inputting the connection information between the IC terminal and the test board terminal.
[0079]
Next, tester information refers to (a) format information of a test program and (b) connection information between a test board terminal and a test terminal (hereinafter, a test terminal) of an IC tester. Since the test program has a different program format for each IC tester, a test program format for each IC tester is stored in advance as a database, and manual input is also supported.
[0080]
Regarding the connection information between the test board terminals and the test terminals, information used for general purposes is prepared as a database, and the other information is manually input.
[0081]
Next, a generally known spice netlist is used as a netlist (circuit diagram information).
[0082]
As is well known, a spice net list indicates circuit information for simulating electric characteristics of an electric circuit, and includes an element name (or an element number), an element type and an attribute, a resistance value / capacitance value, and a value between elements. (Hereinafter referred to as nodes), and information on design values (maximum and minimum values in consideration of variations in semiconductor processes).
[0083]
There are various types of spice netlists, and any of the formats has the following information necessary to generate a test program for resistance check. That is, these pieces of information include (1) element number (including a symbol indicating the type of element), (2) node number of each element, and (3) resistance value (when there is a maximum value and a minimum value, the resistance accuracy is (4) The type and name of the transistor are included.
[0084]
Next, since the information on the resistance accuracy differs depending on the specifications of the device, conditions are specified so that an arbitrary resistance accuracy can be obtained. However, since the resistance accuracy is generally classified into several types, a specification that can be selected when inputting information is adopted.
[0085]
A resistance measurement route is determined, and when a combined resistance value is obtained, a test standard value of a resistance check test program is determined in consideration of resistance accuracy. Actually, since the current flowing when a voltage is applied to both ends of the resistor is used as the test standard, the current value is used as a test standard according to Ohm's law.
[0086]
As an example, when the applied voltage is 0.2 V, the resistance accuracy is ± 10%, and the combined resistance value is 15 kΩ, the resistance test standard is 13.5 kΩ to 16.5 kΩ based on the resistance accuracy and the combined resistance value. The test standard for the current is 12.12 μA to 14.81 μA from the test standard for the applied voltage and the resistance. Therefore, the test standard for the resistance check test program is 12.12 μA to 14.81 μA.
[0087]
Next, referring to FIG. 4 and FIG. 5 which is a circuit diagram showing an example of a resistance check route search of a circuit to be subjected to the method for automatically generating a test program for resistance check according to the present embodiment, the present embodiment will be described using a specific example. The operation of the embodiment will be described.
[0088]
Referring to FIG. 5, this circuit includes a power supply terminal TV for supplying a power supply Vcc, a ground terminal TG for supplying a ground GND, an input terminal TI, a reference voltage terminal TR, an output terminal TO, and resistors R1 to R7. Is an analog processing circuit having:
[0089]
The resistance values of the resistors R1 to R3 are 10, 30, 20 (KΩ).
[0090]
First, it is assumed that the resistance accuracy information 5 describes all the resistance accuracy as ± 10%.
[0091]
In the case of the circuit configuration shown in FIG. 5, the power supply terminal TV and the ground terminal TG are classified into group 1, and the reference voltage terminal TR, the input terminal TI, and the output terminal TO are classified into group 2.
[0092]
First, it is assumed that the power supply terminal TV from the group 1 and the reference voltage terminal TR from the group 2 are selected. When a search is made between the selected two terminals from the reference voltage terminal TR of the group 2 toward the power supply terminal TV of the group 1, the search routes are P1 to P3. Search for a 10 kΩ resistor.
[0093]
The search of the route of P2 is stopped because there is an element (transistor) other than the resistor.
[0094]
Further, the search of the route P3 is stopped because there is an unselected ground terminal TG of the group 1.
[0095]
As a result, a combined resistance (R1) having a resistance value of 10 kΩ exists between the power supply terminal TV and the reference voltage terminal TR. In consideration of the resistance accuracy of ± 10%, the specification of the current value in this case is 9 kΩ to 11 kΩ. The corresponding value is 181.82 μA to 222.22 μA.
[0096]
The voltage application condition is such that the voltage VR = 0.2 V at the reference voltage terminal TR as the search source terminal, and the voltage Vcc = VG (ground potential) at the power supply terminal TV as the search destination terminal.
[0097]
The above test conditions are converted into a test program according to the format of the tester to be used.
[0098]
Then, between the reference voltage terminal TR and the ground terminal TG, between the input terminal TI and the power terminal TV, between the input terminal TI and the ground terminal, between the output terminal TO and the power terminal TV, between the output terminal TO and the ground terminal TG, and A resistance check test program is created by searching for resistances of all routes between the voltage terminal TR and the input terminal TI, between the reference voltage terminal TR and the output terminal TO, and between the input terminal TI and the output terminal TO.
[0099]
In this example, a search result between the reference voltage terminal TR and the ground terminal TG is a resistor R3 having a resistance of 30 KΩ, and a search result between the input terminal TI and the ground terminal is searched for a resistor R2 having a resistance of 20 KΩ.
[0100]
As described above, the present invention has the following effects.
[0101]
The first effect is that a measurement margin can be reduced by generating a resistance check test program capable of performing stable measurement while suppressing the number of series-connected resistors by dividing a route, thereby improving the yield.
[0102]
The second effect is that, due to route division, multiplex measurement of the same resistance can be reduced, so that test program redundancy can be prevented.
[0103]
The third effect is that simultaneous measurement of resistors of different precisions and types can be suppressed by route division, so that the guaranteed quality of the resistors can be improved.
[0104]
The effects of the above three items are due to the following reasons.
[0105]
In the present invention, using the power supply terminal information and the ground terminal information in addition to the conventional netlist, all the terminals of the searched IC internal circuit are classified into a first terminal group including the power supply terminal and the ground terminal and a second terminal group including the signal terminal. The first terminal group, which is a common terminal, is connected to a first terminal group, which is a common terminal, by setting a resistance search route consisting of an arbitrary one terminal selected from each of the first and second terminal groups. The resistance check is performed by dividing the search route and using a common terminal route division algorithm for searching for the resistance value of the resistance element by searching the resistance search route in the direction from the second terminal group to the first terminal group. When selecting a terminal to perform the search, the search is performed with priority given to the combination of the signal terminal-power supply terminal and the signal terminal-ground terminal. The power terminal and the ground terminal are common terminals to which many resistance elements are connected. For example, in a circuit in an IC, there are many combinations in the form of a signal terminal-resistance-ground terminal-resistance-signal terminal. However, since the ground terminal is preferentially selected, two such combinations are surely provided. Can be decomposed into a combination of a signal terminal, a resistor, and a ground terminal.
[0106]
Therefore, it is possible to avoid the first effect of generating a test program in which the resistance is high and the current is small due to the series connection.
[0107]
In addition, since measurement is performed in a more decomposed combination, the second effect is to avoid generation of a test program for measuring the same resistance a plurality of times, and the third effect is to use different types of resistors for which it is difficult to guarantee the resistance value. There is a high possibility of avoiding generation of test programs for simultaneous measurement.
[0108]
Referring to FIG. 9, which is a circuit diagram comparing an example of the first effect with the conventional example, a case where the power supply terminal TV-ground terminal TG which is the conventional worst-case resistance check route shown in FIG. Will measure four series-connected resistances of the resistors R1 to R4 as described in the related art. On the other hand, in the improved resistance check route of the present invention shown in FIG. 9B, the power supply terminal-terminal TI and the terminal TI-ground terminal TG are divided into two, and the resistors R1 and R2 and the resistors R3 and R4 are respectively provided. Is reduced to the measurement of the series connection resistance of each two.
[0109]
FIG. 10 is a circuit diagram showing an example of the second effect in comparison with the conventional example. Referring to FIG. 10A, the input terminal TI2-ground terminal TG and the input terminal TI2 which are the conventional worst-case resistance check routes shown in FIG. When two routes of the output terminal TO are selected, the same resistors R22 and R23 are included in both routes as described in the related art. On the other hand, in the improved resistance check route of the present invention shown in FIG. 10B, the route of the input terminal TI2 to the output terminal TO is divided into two routes of the input terminal TI2 to the ground terminal TG and the output terminal TO to the ground terminal TG. Since they are divided, the resistors R22 and R23 are not included in both of these routes.
[0110]
FIG. 11 is a circuit diagram showing an example of the third effect in comparison with the related art. Referring to FIG. 11, a case where the input terminal TI and the power supply terminal TV which are the conventional worst-case resistance check route shown in FIG. Then, as described in the background art, the resistances of the resistors R3, R2, and R1 having different allowable accuracy are measured in series. If there is an error of 20% outside, that is, there is an error of 2KΩ and there is no other error, it is determined as a non-defective product because it corresponds only to 3.3% of the total resistance value of 60KΩ. On the other hand, in the improved resistance check route of the present invention shown in FIG. 10B, the input terminal TI-the power supply terminal TV is connected to the input terminal TI-ground terminal TG, the reference voltage terminal TR-ground terminal TG, and the reference voltage terminal TR- Since the power supply terminal TV is divided into three loops, the resistances R3, R2, and R1 are measured independently of each other, and the above problem does not occur.
[0111]
【The invention's effect】
As described above, the method and the apparatus for automatically generating a resistance check test program of the present invention use the information of the power supply terminal and the ground terminal in addition to the netlist, and convert all the terminals of the searched IC internal circuit to the power supply terminal and the ground terminal. And a second terminal group consisting of signal terminals, and a resistance search route consisting of an arbitrary one terminal selected from each of the first and second terminal groups is set. Accordingly, the resistance search route is divided by the first terminal group which is a common terminal, and the resistance search route is searched in the direction from the second terminal group to the first terminal group, thereby setting the resistance value of the resistance element. By using the common terminal route division algorithm to be searched, the signal terminal-power supply terminal and the signal terminal-ground Since the search is performed with priority given to the combination of the child, the route of the signal terminal-resistance-ground / power supply terminal-resistance-signal terminal is divided into the combination of each route of the signal terminal-resistance-ground / power supply terminal to obtain the resistance. By generating a resistance check test program capable of stably measuring by suppressing the number of series connections, it is possible to reduce the measurement margin and to improve the yield.
[0112]
Further, since multiple measurements of the same resistance can be reduced, there is an effect that redundancy of the test program can be prevented.
[0113]
Furthermore, since simultaneous measurement of different types of resistors can be suppressed, there is an effect that the guaranteed quality of the resistors can be improved.
[Brief description of the drawings]
FIG. 1 is a flowchart showing one embodiment of a method for automatically generating a resistance check test program according to the present invention.
FIG. 2 is a first half of a flowchart showing details of the processing in FIG. 1;
FIG. 3 is a latter half of a flowchart showing details of the processing in FIG. 1;
FIG. 4 is a block diagram showing an example of a resistance check test program automatic generation device that executes the resistance check test program automatic generation method of the present embodiment.
FIG. 5 is a circuit diagram showing an example of a resistance check route search of a circuit to be automatically generated according to the present embodiment;
FIG. 6 is a block diagram showing an example of a conventional resistance check test program automatic generation device.
FIG. 7 is a flowchart showing an example of a conventional resistance check test program automatic generation method.
FIG. 8 is a circuit diagram showing an example of a resistance check route search of a circuit to be subjected to a conventional resistance check test program automatic generation method.
FIG. 9 is a circuit diagram showing an example of a first problematic resistance check route search of a circuit to be subjected to the conventional resistance check test program automatic generation method in comparison with the first effect of the present invention.
FIG. 10 is a circuit diagram showing a second defective resistance check route search example of a circuit to be subjected to the conventional resistance check test program automatic generation method in comparison with the second effect of the present invention.
FIG. 11 is a circuit diagram showing an example of a third defective resistance check route search of a circuit to be subjected to the conventional resistance check test program automatic generation method in comparison with the third effect of the present invention.
[Explanation of symbols]
1 Netlist
2 Package information
3 Test board information
4 Tester information
5 Resistance accuracy information
6 Power terminal information and ground terminal information
10,100 Resistance check test program generation tool
11 Common terminal route division algorithm
20,200 Resistance check test program

Claims (6)

A resistor for inputting input information including a netlist of an internal circuit of a semiconductor integrated circuit (hereinafter referred to as an IC) to be measured and generating a resistance check test program for evaluating a resistance value of a resistance element inside the IC by an IC tester In the check test program automatic generation method,
Using the information of the power supply terminal and the ground terminal in addition to the netlist, all terminals of the internal circuit searched by the first terminal group consisting of the power supply terminal and the ground terminal, and terminals other than the power supply terminal and the ground terminal Into a second terminal group consisting of certain signal terminals,
By setting a resistance search route composed of arbitrary one terminal selected from each of the first and second terminal groups, the resistance search route is divided by the first terminal group that is a common terminal,
A method of automatically generating a resistance check test program, wherein a resistance value of the resistance element is searched by searching the resistance search route from the second terminal group to the first terminal group. A resistor for inputting input information including a netlist of an internal circuit of a semiconductor integrated circuit (hereinafter referred to as an IC) to be measured and generating a resistance check test program for evaluating a resistance value of a resistance element inside the IC by an IC tester In the check test program automatic generation method,
A first step of inputting input information including the netlist of the IC, resistance accuracy information, power supply terminal information, and ground terminal information;
All terminals of the searched internal circuit are grouped into a first terminal group consisting of the power supply terminal and the ground terminal, and a second terminal group consisting of signal terminals that are terminals other than the power supply terminal and the ground terminal, The resistance search route is divided by the first terminal group, which is a common terminal, by setting a resistance search route including an arbitrary one terminal selected from each of the first and second terminal groups. A second method of searching for a resistance of a resistance to be measured and calculating a test standard using a common terminal route division algorithm which is a specific algorithm for searching for a search route from the second terminal group in the direction of the first terminal group. Steps and
A third step of associating each of the input information with each other and generating the resistance check test program based on the associated input information and the calculated test standard. The first step includes inputting the netlist of the IC, package information, test board information, tester information, the resistance accuracy information, and the input information including power supply terminal information and ground terminal information. 3. The method of automatically generating a resistance check test program according to claim 2, wherein: The second step extracts all terminals of the netlist, classifies the power terminals and the ground terminals into the first terminal group based on the power terminal information and the ground terminal information, and Classifying signal terminals other than terminals into the second terminal group;
Selecting a two-terminal search root terminal composed of an arbitrary one terminal from all the terminals of the first terminal group and all the terminals of the second terminal group;
A twenty-first step of searching for a route of a resistor connected between two terminals of a search route terminal selected only in a direction from the second terminal group to the first terminal group;
It is determined whether or not there is an unselected terminal of the first terminal group in a search route that is a route of the resistor searched in the twenty-first step, and if there is an unselected terminal, the process returns to the twenty-first step. 22 steps,
In the 22nd step, if there is no unselected terminal, it is determined whether or not there is an element other than a resistor in the search route. If there is an element other than a resistor, the process returns to the 21st step. When,
In the twenty-third step, if there is no element other than a resistor in the search route, it is determined whether or not the entire route between the selected two terminals has been searched. A twenty-fourth step returning to the step of
In the twenty-fourth step, when the search of the all routes is completed, a twenty-fifth step of obtaining a combined resistance value of all the resistances of the search route and calculating a test standard based on the information of the resistance accuracy,
A twenty-sixth step of storing the information of the two selected search route terminals, the combined resistance value, and the test standard;
A twenty-seventh step of determining whether or not the route search has been completed for all combinations of the terminals of the first terminal group and the second terminal group;
In the twenty-seventh step, when the route search is not completed for the combination of all the terminals, terminals of the combination for which search has not been completed are selected one terminal at a time from the first terminal group and the second terminal group. A twenty-eighth step returning to the twenty-first step S21;
In the twenty-seventh step, when the route search is completed with the combination of all the terminals, a combination of any two terminals of the second terminal group is selected as the search root terminal, and the selected search root terminal is selected. 3. A resistance search step for a second terminal group, wherein a resistance connected between the two terminals is searched for a combination of terminals of all the second terminal groups. Check test program automatic generation method. A twenty-ninth step in which the resistance search step of the second terminal group selects a route composed of an arbitrary combination of two terminals of the second terminal group as the search route;
A thirtieth step of searching for a resistance connected between the two terminals of the selected search route;
Determining whether there is a terminal of the first terminal group in the search route, and if there is a terminal of the first terminal group, a 31st step of returning to the 30th step;
In the thirty-first step, if there is no terminal of the first terminal group, it is determined whether or not there is an element other than a resistor in the search route, and if there is an element other than a resistor in the search route, A thirty-second step returning to the thirtieth step;
In the thirty-second step, when there is no element other than the resistor in the search route, it is determined whether or not the search of all the routes of the selected two terminals is completed, and the search of all the routes of the selected two terminals is performed. Is not completed, a 33rd step returning to the 30th step;
A step of calculating a test standard based on the information of the resistance accuracy by obtaining a combined resistance value of the search route when the search of all the routes of the selected two terminals is completed in the 33rd step; ,
A thirty-fifth step of storing the information of the selected two terminals, the combined resistance value and the test standard;
A thirty-sixth step of determining whether or not a route search has been completed for all combinations of terminals in the second terminal group;
In the thirty-sixth step, if the route search is not completed, a thirty-seventh step is to select two terminals of an unselected combination from the second terminal group and return to the thirtieth step. 5. The method of automatically generating a resistance check test program according to claim 4, wherein A resistor for inputting input information including a netlist of an internal circuit of a semiconductor integrated circuit (hereinafter referred to as an IC) to be measured and generating a resistance check test program for evaluating a resistance value of a resistance element inside the IC by an IC tester In a resistance check test program automatic generation device including a check test program generation tool,
The netlist of the IC, the power terminal information and the ground terminal information, the package information, the test board information, the tester information, and the resistance accuracy information are input,
A first terminal group including a power supply terminal and a ground terminal, wherein the resistance check test program generation tool utilizes information of a power supply terminal and a ground terminal in addition to the netlist, and searches all terminals of the IC internal circuit; The resistance search route is divided into a second terminal group consisting of signal terminals which are terminals other than the power supply terminal and the ground terminal, and a resistance search route consisting of arbitrary one terminal selected from each of the first and second terminal groups. By setting, the resistance search route is divided by the first terminal group which is a common terminal, and the resistance search route is searched from the second terminal group toward the first terminal group by searching for the resistance search route. A resistance check having a common terminal route splitting algorithm which is a specific algorithm for searching for a resistance value of a resistance element. Strike program automatic generation system.

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